Numerous virtual “power meters” let you find out how much of your laptop’s battery remains before it needs a recharge. But these meters do not display power drainage in real time. For this you will need to use PwrDrain.

PwrDrain is an open source desktop widget for Windows laptops that displays the current power drainage in real time. In addition to displaying drainage data, the app alerts you when you are about to run a tool that requires a lot of power.

Written in HTML, CSS and JavaScript, the widget helps identify which programs are taking up a lot of power. Data is collected through Windows Management Instrumentation by using Advanced Configuration & Power Interface.